Antenna device, radio device, and electronic instrument

ABSTRACT

An antenna apparatus  1  has an antenna substrate  21  composed of a separator  23  and electrolyte layers  24   a  and  24   b  disposed on both surfaces of the separator  23 ; an antenna pattern  22   a  disposed on the solid electrolyte layer  24   a ; and an antenna pattern  22   b  disposed on the solid electrolyte layer  24   b . The antenna patterns  22   a  and  22   b  are made of an electroconductive plastic. When a DC voltage is applied between the antenna patterns  22   a  and  22   b , ions can be doped to one of the antenna patterns  22   a  and  22   b , whereas ions can be undoped form the other of the antenna patterns  22   a  and  22   b . In other words, one of the antenna patterns  22   a  and  22   b  can become a conductor, whereas the other thereof can become an insulator.

TECHNICAL FIELD

The present invention relates to an antenna apparatus having a pluralityof antenna elements; a wireless apparatus therewith; and an electronicapparatus therewith.

BACKGROUND ART

In recent years, a wireless communication function has been mounted onnot only information processing devices, such as personal computers, andcommunication terminal devices, such as cellular phones and PDAs(Personal Digital Assistances), but also various types of consumerelectronic devices, such as audio devices, video devices, cameradevices, printers, and entertainment robots. In addition, the wirelesscommunication function has been mounted on wireless LAN (Local AreaNetwork) access points and small accessory cards. The accessory cardsare wireless card modules having both a storage function and a wirelesscommunication function. Known as wireless card modules are for examplePCMCIA (Personal Computer Memory Card International Association) typecards, compact flash cards, mini PCI (Peripheral ComponentInterconnection) cards.

As the wireless communication function has been mounted on variousdevices, antennas that receive and transmit radio waves have neededvarious shapes and characteristics. For example, antennas that can dealwith a wide frequency band and multiple frequencies have been needed.

For example, for 5 GHz band used in the wireless LAN, antennas have beenneeded for 4.9 GHz band and 5.8 GHz band that are wider than theexisting 5.15 to 5.35 GHz bands. In addition, to satisfy the IEEE(Institute of Electrical and Electronics Engineers) 802.11a/b/gstandards, antennas are needed to cover both the frequency bands 2.4-2.5GHz and 5.15-5.35 GHz. In an ultra wide band (UWB), which is gainingattention, antennas need to cover wide bands of 3.1 GHz-10.6 GHz. Thereis a possibility that the UHF bands (400-800 MHz) of ground wave digitalbroadcasts and high speed wide band milli-wave communication systems (25GHz band, 60 GHz band, and so forth) will be combined in future.

So far, to cover a plurality of frequencies, the following methods havebeen proposed: (1) an antenna is designed to have a main resonance and asub resonance, and (2) an antenna is designed to broaden a frequencyband with one resonance. The method (1) of these methods has been widelyused in many commercial antennas.

However, these methods have the following problems. The method (1)sacrifices characteristics such as “deterioration of return losscharacteristics” “narrow frequency band” in one of a plurality of bands.In contrast, the method (2) sacrifices a gain of a radio wave in awidened band because the band and gain have a reversely proportionalrelationship.

In an ideal method of widening a frequency band, which has beenproposed, a plurality of antenna elements corresponding to necessaryfrequency bands are mounted on a device (as disclosed in for exampleJapanese Patent Laid-Open Publication No. 2002-92576).

FIG. 17 shows an example of an antenna substrate having a plurality ofantenna patterns. FIG. 17A is a plan view showing one principal surfaceS₃ of an antenna substrate 101. FIG. 17B is a plan view showing anotherprincipal surface S₄ of the antenna substrate 101. As shown in FIG. 17Aand FIG. 17B, the principal surface S₃ of the antenna substrate 101 hasa first antenna pattern 102 a. The other principal surface S₄ of theantenna substrate 101 has a second antenna pattern 102 b. The firstantenna pattern 102 a is an antenna pattern corresponding to frequencybands 4.9-5.35 GHz, an antenna pattern corresponding to frequency bands2.4-2.5 GHz, or an antenna pattern for a DT (Digital Television)corresponding to frequency bands 400-800 MHz. The second antenna pattern102 b is an antenna pattern corresponding to frequency bands 5.35GHz-5.8 GHz or an antenna pattern corresponding to milli-wave bands.

However, if a plurality of antenna patterns are closely disposed andmounted on a device, they interfere with each other and theircharacteristics deteriorate. To solve this problem, if a plurality ofantenna patterns are disposed with sufficient clearance areas, the sizeof the device becomes large.

If the antenna substrate 101 shown in FIG. 17 is thinned out (forexample, 1 mm or less), the first antenna pattern 102 a and the secondantenna pattern 102 b disposed on both the principal surfaces largelyinterfere with each other. As a result, characteristics of the antennadeteriorate. Thus, as shown in FIG. 18, the first antenna pattern 102 aand the second antenna pattern 102 b have to be disposed on the antennasubstrate 101 with a sufficient clearance area.

As described above, when a plurality of antenna elements are mounted ona device, the size of the device becomes large. Thus, this method doesnot satisfy the present needs of which the wireless function is mountedon various consumer devices. Thus, under the existing circumstances,such a method has been hardly used in real devices.

Therefore, an object of the present invention is to provide an antennaapparatus that allows a plurality of antenna patterns to be closelydisposed and deterioration of characteristics due to interference ofantenna patterns to be suppressed; a wireless apparatus therewith; andan electronic apparatus therewith.

DISCLOSURE OF THE INVENTION

To solve the foregoing problem, the first invention is an antennaapparatus, comprising:

a substrate; and

a plurality of antenna patterns disposed on the substrate,

wherein the antenna patterns being made of an electroconductive plastic,and

wherein the substrate is made of a solid electrolyte.

In the first invention, it is preferred that the substrate also have aseparator and that solid electrolyte layers made of the solidelectrolyte be disposed on both surfaces of the separator. The pluralityof antenna patterns typically correspond to different frequency bands.The plurality of antenna patterns are typically linear patterns.

In the first invention, the substrate is typically a planar substrate.The plurality of antenna patterns are typically disposed on either orboth principal surfaces of the substrate. When the plurality of antennapatterns are disposed on one principal surface of the substrate, it ispreferred that a base plate made of a metal be disposed on the otherprincipal surface of the substrate. When the base plate made of a metalis disposed on the other principal surface of the substrate, theplurality of antenna patterns are typically planner patterns.

According to the first invention, by applying the DC voltage between theplurality of antenna patterns disposed on the solid electrolyte, ionscan be doped from the substrate to an antenna pattern having onepotential, whereas ions can be undoped from another antenna patternhaving the other potential to the substrate. In other words, with apotential difference between the antenna patterns, the antenna patternhaving one potential can become a conductor, whereas the antenna patternhaving the other potential can become an insulator.

The second invention is a wireless apparatus that is connected to adevice and that allows it to additionally have a wireless function, thewireless apparatus comprising:

a substrate;

a plurality of antenna patterns disposed on the substrate; and

a switch that selects the plurality of antenna patterns so that one ofthe plurality of antenna patterns has one potential and the other of theplurality of antenna patterns has another potential when a DC voltage isapplied between the plurality of antenna patterns;

wherein the antenna patterns are made of an electroconductive plastic,and

wherein the substrate is made of a solid electrolyte.

In the second invention, it is preferred that the substrate also have aseparator and that solid electrolyte layers made of the solidelectrolyte be disposed on both surfaces of the separator. The pluralityof antenna patterns typically correspond to different frequency bands.The plurality of antenna patterns are typically linear patterns.

In the second invention, the substrate is typically a planar substrate.The plurality of antenna patterns are typically disposed on either orboth principal surfaces of the substrate. When the plurality of antennapatterns are disposed on one principal surface of the substrate, it ispreferred that a base plate made of a metal be disposed on the otherprincipal surface of the substrate. When the base plate made of a metalis disposed on the other principal surface of the substrate, theplurality of antenna patterns are typically planner patterns.

According to the second invention, by applying the DC voltage betweenthe plurality of antenna patterns disposed on the solid electrolyte,ions can be doped from the substrate to an antenna pattern having onepotential, whereas ions can be undoped from another antenna patternhaving the other potential to the substrate. In other words, with apotential difference between the antenna patterns, the antenna patternhaving one potential can become a conductor, whereas the antenna patternhaving the other potential can become an insulator.

The third invention is an electronic apparatus having a wirelesscommunication function that transmits and receives information, theelectronic apparatus comprising:

a substrate;

a plurality of antenna patterns disposed on the substrate;

a voltage source that applies a DC voltage between the plurality ofantenna patterns; and

a switch that selects the plurality of antenna patterns so that one ofthe plurality of antenna patterns has one potential and the other of theplurality of antenna patterns has another potential when the DC voltageis applied between the plurality of antenna patterns,

wherein the antenna patterns are made of an electroconductive plastic,and

wherein the substrate is made of a solid electrolyte.

In the third embodiment, it is preferred that the substrate also have aseparator and that solid electrolyte layers made of the solidelectrolyte be disposed on both surfaces of the separator. The pluralityof antenna patterns typically correspond to different frequency bands.The plurality of antenna patterns are typically linear patterns.

In the third embodiment, the substrate is typically a planer substrate.The plurality of antenna patterns are typically disposed on either orboth principal surfaces of the substrate. When the plurality of antennapatterns are disposed on one principal surface of the substrate, it ispreferred that a base plate made of a metal be disposed on the otherprincipal surface of the substrate. When the base plate made of a metalis disposed on the other principal surface of the substrate, theplurality of antenna patterns are typically planner patterns.

According to the third invention, by applying the DC voltage between theplurality of antenna patterns disposed on the solid electrolyte, ionscan be doped from the substrate to an antenna pattern having onepotential, whereas ions can be undoped from another antenna patternhaving the other potential to the substrate. In other words, with apotential difference between the antenna patterns, the antenna patternhaving one potential can become a conductor, whereas the antenna patternhaving the other potential can become an insulator.

As described above, according to the present invention, by applying theDC voltage between the plurality of antenna patterns disposed on thesolid electrolyte, ions can be doped from the substrate to an antennapattern having one potential, whereas ions can be undoped from anotherantenna pattern having the other potential to the substrate. In otherwords, with a potential difference between the antenna patterns, theantenna pattern having one potential can become a conductor, whereas theantenna pattern having the other potential can become an insulator.Thus, even if the plurality of antenna elements are closely disposed,deterioration of characteristics due to interference of the antennaelements can be suppressed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram showing an example of an electronicapparatus to which a wireless apparatus according to a first embodimentof the present invention is mounted;

FIG. 2 is a perspective view showing an example of a wireless apparatus1 disposed in a housing;

FIG. 3 is a plan view showing an antenna apparatus according to thefirst embodiment of the present invention;

FIG. 4 is a schematic diagram showing examples of antenna patterns;

FIG. 5 is a sectional view showing an example of the structure of theantenna apparatus according to the first embodiment of the presentinvention;

FIG. 6 is a block diagram showing an example of the structure of anantenna apparatus control circuit disposed in the wireless apparatusaccording to the first embodiment of the present invention;

FIG. 7 is a block diagram showing an example of the structure of asignal process circuit disposed in the wireless apparatus according tothe first embodiment of the present invention;

FIG. 8 is a sectional view describing an example of the operation of thewireless apparatus according to the first embodiment of the presentinvention;

FIG. 9 is a sectional view showing an example of the structure of anantenna apparatus according to a second embodiment of the presentinvention;

FIG. 10 is a block diagram showing an example of the structure of anantenna apparatus control circuit disposed in a wireless apparatusaccording to the second embodiment of the present invention;

FIG. 11 is a sectional view describing an example of the operation ofthe wireless apparatus according to the second embodiment of the presentinvention;

FIG. 12 is a sectional view showing an example of the structure of awireless apparatus according to a third embodiment of the presentinvention;

FIG. 13 is a block diagram showing an example of the structure of anantenna apparatus control circuit disposed in the wireless apparatusaccording to the third embodiment of the present invention;

FIG. 14 is a sectional view showing an example of the structure of anantenna apparatus according to a fourth embodiment of the presentinvention;

FIG. 15 is a block diagram showing an example of the structure of anantenna apparatus control circuit disposed in a wireless apparatusaccording to the fourth embodiment of the present invention;

FIG. 16 is a block diagram showing an example of the structure of asignal process circuit disposed in the wireless apparatus according tothe fourth embodiment of the present invention;

FIG. 17 is a schematic diagram showing a conventional antenna apparatus;and

FIG. 18 is a schematic diagram showing a conventional antenna apparatus.

BEST MODES FOR CARRYING OUT THE INVENTION

Next, with reference to the accompanying drawings, embodiments of thepresent invention will be described. In all the drawings of theembodiments of the present invention, similar or corresponding elementsare denoted by similar or corresponding reference numerals.

FIG. 1 shows an example of an electronic apparatus to which a wirelessapparatus 1 according to a first embodiment of the present invention isattached. The wireless apparatus 1 is composed of a wireless apparatusmain body 3 and an antenna apparatus 2 disposed at one end of thewireless apparatus main body 3. The wireless apparatus 1 is a wirelesscard module that has for example a storage function and a wirelesscommunication function. The wireless card module is for example a PCMCIAtype card, a compact flash card, a mini PCI card, or the like.

The wireless apparatus 1 has a structure that can be freely attached toand detached from a slot 12 disposed in an electronic apparatus 11 suchas a personal computer. Specifically, as shown in FIG. 1, the wirelessapparatus 1 is attached to the slot 12 so that one end of the wirelessapparatus main body 3, which is the antenna apparatus 2, protrudes fromthe electronic apparatus 11. With the wireless apparatus 1, apredetermined extension function and a wireless communication functionare provided to the electronic apparatus 11. In addition, the wirelessapparatus 1 has a storage function that exchanges data with theelectronic apparatus 11.

FIG. 2 is a perspective view showing an example of the wirelessapparatus 1 disposed in a housing. As shown in FIG. 2, the wirelessapparatus main body 3 is composed of a main body substrate 31 having arectangle shape viewed from the above of its principal surface; aconnection terminal 32 disposed on one shorter side of the rectangle;and a circuit portion 33 disposed at a center portion of the wirelessapparatus 1. The connection terminal 32 is a connector portion based onfor example the PCMCIA standard. By inserting the connection terminal 32of the wireless apparatus 1 into the slot 12 of the electronic apparatus11, the connection terminal 32 and a corresponding connection terminaldisposed inside the slot 12 are connected. As a result, the electronicapparatus 11 is provided with the wireless function. The circuit portion33 has for example an antenna control circuit, a signal process circuit,and a storage function memory device.

The antenna apparatus 2 mainly has a planar antenna substrate 21 and aplurality of antenna patterns 22 disposed on both principal surfaces ofthe antenna substrate 21. The antenna apparatus 2 is disposed on theother shorter side opposite to the connection terminal 32. The antennaapparatus 2 has a rectangle shape viewed from its principal surface. Thelength of each of the longer sides of the rectangle is slightly smallerthan the width of the main body substrate 31. The length of each of theshorter sides of the antenna apparatus 2 is slightly larger than theheight of the opening of the slot 12 of the electronic apparatus 11. Alonger side portion of the antenna apparatus 2 has a connection portionthat connects the antenna apparatus 2 and the main body substrate 31.

FIG. 3A is a plan view showing one principal surface of the antennaapparatus 2 according to the first embodiment of the present invention.FIG. 3B is a plan view showing the other principal surface of theantenna apparatus 2 according to the first embodiment of the presentinvention. As shown in FIG. 3A, an antenna pattern 22 a is disposed onone principal surface S₁ of the antenna substrate 21. An antenna pattern22 b is disposed on the other principal surface S₂ of the antennasubstrate 21. Electrodes 25 a and 25 b are disposed on the antennapattern 22 a on the connection portion side of the antenna substrate 21.Electrodes 26 a and 26 b are disposed on the antenna pattern 22 b on theconnection portion side of the antenna substrate 21. The electrodes 25a, 25 b, 26 a, and 26 b are made of for example a metal such as copper.The electrodes 25 a and 25 b are connected to the signal process circuitof the circuit portion 33. The electrodes 25 b and 26 b are connected toa ground pattern disposed on the circuit portion 33.

The antenna patterns 22 a and 22 b correspond to different frequencybands. The frequency bands are for example 5 GHz bands, 2.4 GHz bands,milli-wave bands, micro-wave bands, and UHF bands.

FIG. 4 shows examples of the antenna patterns 22. The antenna patterns22 are for example linear patterns or planar patterns. The linearpatterns are for example Zepp type (FIG. 4A), monopole type (FIG. 4B),dipole type (FIG. 4C), inverse F type, and meander type. The plannerpatterns are for example micro-strip type antenna, and PIFA (PlanerInverted F Antenna). When the antenna patterns 22 a and 22 b aremono-pole type antenna elements, the antenna apparatus 2 is provide witha base plate. When the antenna patterns 22 a and 22 b are dipole typeantenna elements, they are balance-fed.

FIG. 5 is a sectional view showing an example of the structure of theantenna substrate 21. As shown in FIG. 5, the antenna substrate 21 iscomposed of an electrolyte layer 24 b, a separator 23, and anelectrolyte layer 24 a that are layered in the order. The antennapatterns 22 a and 22 b are disposed on the electrolyte layers 24 a and24 b, respectively.

The antenna patterns 22 a and 22 b are made of an electroconductiveplastic. When the electroconductive plastic is doped with ions, itbecomes an electroconductive resin like a metal. When theelectroconductive plastic is undoped, it becomes an insulative resin. Asthe electroconductive plastic that can be used and known is for examplepolyacetylene, polythiophene, polypyrrole, polyaniline, or polyazulen.

The antenna patterns 22 a and 22 b can be disposed in one of thefollowing methods. As one method, molten electroconductive plastic iscoated on the electrolyte layers 24 a and 24 b for desired patterns andthen hardened. As another method, after molten electroconductive plasticis shaped in desired antenna patterns and hardened, they are disposed onthe electrolyte layers 24 a and 24 b. As another method, film-shapedelectroconductive plastic is formed by electrolytic polymerization. Theelectroconductive plastic is cut or punched out in desired shapes anddisposed on the electrolyte layers 24 a and 24 b.

It is preferred that the antenna patterns 22 a and 22 b be stablysecured on the solid electrolyte layers 24 a and 24 b, respectively. Asa stably securing method, the antenna patterns 22 a and 22 b are adheredto the solid electrolyte layers 24 a and 24 b, respectively, with anadhesive agent. As another method, the antenna patterns 22 a and 22 bare coated with a sheet. As another method, concave portionscorresponding to the shapes of the antenna patterns 22 a and 22 b areformed in the solid electrolyte layers 24 a and 24 b, respectively. Theantenna patterns 22 a and 22 b are fit to the concave portions. Asanother method, several positions of the antenna patterns 22 a and 22 bare secured to the solid electrolyte layers 24 a and 24 b with securingmembers or the like. As another method, these methods may be combined.When the antenna patterns 22 a and 22 b are adhered to the solidelectrolyte layers 24 a and 24 b with adhesive agent, the thickness ofthe adhesive agent needs to be decreased so that ions can easilymigrate. In addition, it is preferred that the antenna patterns 22 a and22 b and the solid electrolyte layers 24 a and 24 b be adhered atseveral positions with adhesive agent so that ions are not preventedfrom migrating. When the antenna patterns 22 a and 22 b are secured tothe solid electrolyte layers 24 a and 24 b with securing members or thelike, it is preferred that easily peelable portions of the antennapatterns 22 a and 22 b be secured. It is preferred that the material ofthe sheet that covers the antenna patterns 22 a and 22 b be a materialthat is free of deterioration of radio wave characteristics thereof andthat has flexibility. The material of the sheet is for examplepolycarbonate (PC), acrylonitorile-butadiene-styrene (ABS), orpolyimide.

The solid electrolyte layers 24 a and 24 b have a rectangle shape viewedfrom the above of their principal surfaces. The solid electrolyte layers24 a and 24 b contain ions (dopants) that are doped to electroconductiveplastic. These ions are cations or anions. The solid electrolyte thatcomposes the solid electrolyte layers 24 a and 24 b are for examplesolid electrolyte used for battery cells such as lithium ion batterycells (lithium polymer battery cells), and fuel battery cells.

The solid electrolytic that composes the solid electrolyte layers 24 aand 24 b may be inorganic electrolyte, polymer electrolyte, or gel-typeelectrolyte of which electrolyte is mixed with a highly polymerizedcompound. The gel-type electrolyte is composed of for exampleplasticizing agent containing lithium salt and 2% to 30% by percent of amatrix polymer. At this point, an ester group, an ether group, or acarbonate group may be used as a single component or one component ofplasticizing agent.

As a polymeric material of the solid electrolyte layers 24 a and 24 b,for example silicon gel, acrylic gel, polysaccharide group polymer,acrylonitrile gel, polyphosphazen denatured polymer, polyethylene oxide,polypropylene oxide, composite polymer thereof, cross-linked polymerthereof, or denatured polymer thereof, fluorinated polymer, such aspoly(vinylidene fluororide), poly(vinylidenefluororide-co-hexafluoropropylene), poly(vinylidenefluororide-co-tetrafluoropropylene), poly(vinylidenefluororide-co-trifluoropropylene), or a mixture thereof can be used.

The electrolyte salt is for example lithium salt or sodium salt. Thelithium salt is for example a regular lithium salt used for anelectrolytic solution of a regular battery cell. The lithium salt is forexample as follows, but not limited thereto.

The lithium salt is for example lithium chloride, lithium bromide,lithium iodide, lithium chlorate, lithium perchlorate, lithium bromate,lithium iodate, lithium nitrate, tetrafluoro lithium borate, hexafluorolithium phosphate, lithium acetate, bis(trifluoro methane sulfonyl)imidolithium, LiAsF₆, LiCF₃SO₃, LiC(SO₂CF₃)₃, LiAlCl₄, or LiSiF₆. Asingle compound or a mixture of two or more compounds of these lithiumcompounds may be used.

The separator 23 has a rectangle sheet shape when viewed from the aboveof its principal surface. The separator 23 is used to separate the solidelectrolyte layers 24 a and 24 b. As the separator 23, a separator thatis known for regular battery cells can be used. The separator 23 is forexample a porous film made of a polyolefin type material such aspolypropylene or polyethylene; a porous film made of an inorganicmaterial such as a nonwoven substance of a ceramic material; or alaminate of two or more types of these materials. In consideration ofthe strength of the antenna substrate 21, it is preferred that theseparator 23 be disposed. However, the separator 23 may be omitted.

FIG. 6 is a block diagram showing an example of the structure of anantenna apparatus control circuit that controls the antenna apparatus 2according to the first embodiment of the present invention. As shown inFIG. 6, the antenna apparatus control circuit mainly has bias circuits45 and 46 and switches 42, 43, and 44. The switch device 42 is connectedto a radio frequency signal circuit block 41.

Disposed on the principal surface S₁ of the planer planar antennasubstrate 21 is the antenna pattern 22 a. Disposed on the otherprincipal surface S₂ is the antenna pattern 22 b. The antenna pattern 22a disposed on the principal surface S₁ is connected to a terminal 43 aof the switch device 43 through the bias circuit 45. A terminal 43 b ofthe switch device 43 is connected to a voltage source (not shown). Aterminal 43 c of the switch device 43 is grounded.

The antenna pattern 22 b disposed on the principal surface S₂ of theantenna apparatus 2 is connected to a terminal 44 a of the switch device44 through the bias circuit 46. A terminal 44 b of the switch device 44is connected to the voltage source (not shown). A terminal 44 c of theswitch device 44 is grounded.

The antenna pattern 22 a disposed on the principal surface S₁ of theantenna apparatus 2 is connected to a terminal 42 b of the switch device42. The antenna pattern 22 b disposed on the other surface S₂ of theantenna apparatus 2 is connected to a terminal 42 c of the switch device42. A terminal 42 a of the switch device 42 is connected to the radiofrequency circuit block 41.

For example, a DC voltage V_(DC) is applied between the terminal 43 band the terminal 44 c. The DC voltage V_(DC) is applied between theterminal 44 b and the terminal 43 c. Specifically, the DC voltage V_(DC)is applied between the terminal 43 b and the terminal 44 c so that thepotential of the terminal 43 b side (the antenna 22 a side) becomeshigher than that of the terminal 44 c side. The DC voltage V_(DC) isapplied between the terminal 44 b and the terminal 44 c so that thepotential of the terminal 44 b side (the antenna 22 b side) becomeshigher than that of the terminal 44 c side.

The bias circuits 45 and 46 stably apply voltages to the antennaapparatus 2. The switch device 42 connects the radio frequency circuitblock 41 to one of the antenna patterns 22 a and 22 b. The switchdevices 43 and 44 select the antenna pattern 22 a or 22 b to which theDC voltage V_(DC) is applied so that the potential of the selectedantenna pattern becomes higher than that of the non-selected antennapattern. Specifically, when the terminals 43 a and 43 b are connectedand the terminals 44 a and 44 c are connected, the DC voltage V_(DC) isapplied between the antenna patterns 22 a and 22 b so that the potentialof the antenna pattern 22 a becomes higher than that of the antennapattern 22 b. When the terminals 44 a and 44 b are connected and theterminals 43 a and 43 c are connected, the DC voltage V_(DC) is appliedbetween the antenna patterns 22 a and 22 b so that the potential of theantenna pattern 22 b becomes higher than that of the antenna pattern 22a. The switch devices 43 and 44 are controlled with a control signalsupplied from for example the electronic apparatus 11. To miniaturizethe entire apparatus including the switch devices 42, 43, and 44, it ispreferred that the switch devices 42, 43, and 44 be semiconductorswitches (switch ICs (Integrated Circuits)) or RF-MEMSs (Micro ElectroMechanical System) switches.

FIG. 7 is a block diagram showing an example of the structure of thesignal process circuit disposed in the wireless apparatus 1 according tothe first embodiment of the present invention. As shown in FIG. 7, thesignal process circuit is composed of a host interface (hereinafterreferred to as the host I/F) 51, base band circuits (hereinafterreferred to as the BB circuits) 52 ₁ and 52 ₂, radio frequency signalprocess circuits (hereinafter referred to as the RF circuits) 53 ₁ and53 ₂, a switch device 54, and a switch device 55.

The host I/F 51 allows the wireless apparatus 1 to communicate with theelectronic apparatus 11. The BB circuits 52 ₁ and 52 ₂ are controlcircuits that perform processes such as modulation and demodulation ofsignals. The RF circuits 53 ₁ and 53 ₂ are circuits that transmit andreceive radio frequency signals. The RF circuit 53 ₁ and the BB circuit52 ₁ are circuits that correspond to the antenna pattern 22 a. The RFcircuit 53 ₂ and the BB circuit 52 ₂ are circuits that correspond to theantenna pattern 22 b. When the wireless apparatus 1 is an apparatusaccording to the IEEE 802.11a/b/g standards, the antenna pattern 22 a,the RF circuit 53 ₁, and the BB circuit 52 ₁ are an antenna and circuitsthat correspond to 5 GHz bands (IEEE 802.11a), whereas the antennapattern 22 a, the RF circuit 53 ₂, and the BB circuit 52 ₂ are anantenna and circuits that correspond to 2.4 GHz bands (IEEE 802.11b/g).

The switch device 54 selects the RF circuit 53 ₁ or 53 ₂ to be connectedto the switch device 55. The switch device 55 selects the antennapattern 22 a or 22 b to be connected to the switch device 54.

Next, the operation of the wireless apparatus 1 according to the firstembodiment of the present invention will be described.

FIG. 8 is a sectional view describing an example of the operation of thewireless apparatus 1 according to the first embodiment. Next, withreference to FIGS. 6 and 8, an example of the operation of the wirelessapparatus 1 according to the first embodiment will be described. In thisexample, it is assumed that ions doped to the antenna patterns 22 a and22 b are anions.

First, the terminals 43 a and 43 b of the switch device 43 shown in FIG.6 are connected. The terminals 44 a and 44 c of the switch device 44 areconnected. As a result, the DC voltage V_(DC) is applied to the antennaapparatus 2 so that the potential of the antenna pattern 22 a disposedon the principal surface S₁ becomes high and the potential of theantenna pattern 22 b disposed on the principal surface S₂ becomes low.In other words, a DC current i_(DC) flows as shown in FIG. 8.

When the voltage is applied, as shown in FIG. 8, ions of the antennapattern 22 b migrate to the solid electrolyte layer 24 b. In contrast,ions of the solid electrolyte layer 24 a migrate to the antenna pattern22 a. Thus, the antenna pattern 22 b becomes an insulator, whereas theantenna pattern 22 a becomes a conductor. In other words, only theantenna pattern 22 a, which has been doped with ions, functions as anantenna. Thereafter, the terminals 42 a and 42 b of the switch device 42are connected. As a result, a radio frequency signal is supplied formthe radio frequency circuit block 41 to the antenna pattern 22 adisposed on the principal surface S₁.

According to the first embodiment of the present invention, thefollowing effects can be obtained.

The antenna apparatus 2 has the separator 23; the antenna substrate 21composed of the solid electrolyte layers 24 a and 24 b disposed on bothsurfaces of the separator 23; the antenna pattern 22 a disposed on thesolid electrolyte layer 24 a; and the antenna pattern 22 b disposed onthe solid electrolyte layer 24 b. When the DC voltage V_(DC) is appliedbetween the antenna patterns 22 a and 22 b, ions can be doped to one ofthe antenna patterns 22 a and 22 b, whereas ions can be undoped from theother. In other words, using the potential difference between theantenna patterns 22 a and 22 b, one of the antenna patterns 22 a and 22b can become a conductor, whereas the other can become an insulator.Thus, in the antenna apparatus 2, where the two antenna patterns 22 aand 22 b are closely disposed, namely, in the antenna apparatus 2, whichhas the antenna substrate 21, which does not have radio wave shieldcharacteristics and is very thin, the antenna patterns 22 a and 22 bdisposed on both surfaces of the antenna substrate 21, the antennapatterns 22 a and 22 b do not interfere with each other. Thus,deterioration of the characteristic of the antenna apparatus 2 due tointerference of the antenna patterns 22 a and 22 b can be suppressed. Asa result, the areas of the antenna patterns 22 a and 22 b can beremarkably decreased. In addition, the degree of freedom of design ofthe antenna apparatus 2 can be remarkably improved.

In addition, since the antenna patterns 22 a and 22 b, which are made ofan electroconductive plastic, are disposed on the solid electrolytelayers 24 a and 24 b and the antenna patterns 22 a and 22 b are activelyselected from one to the other with a DC current, unlike the case thatthe plurality of antenna patterns are made of a metal, even if they areclosely disposed, deterioration of the characteristics of the antennaapparatus 2 due to interference of the antenna patterns 22 a and 22 bcan be suppressed.

In addition, a plurality of antenna patterns 22 a and 22 b for differentfrequency bands corresponding to for example milli-wave bands, IEEE802.11a/b/g, DTV (Digital Television) tuner, and so forth can be closelydisposed without deterioration of the characteristics of the antennaapparatus 2. Thus, the antenna apparatus 2, which can deal withmulti-frequency bands and that is small, the wireless apparatus 1therewith, and the electronic apparatus therewith can be provided.

In addition, various types of antenna patterns such as Zepp, monopole,dipole, and patch antenna patterns can be freely disposed on either orboth principal surfaces of the antenna substrate 21. Thus, the degree offreedom of design of the antenna apparatus 2 can be improved.

In addition, unlike antenna patterns made of a hard metal, since theantenna patterns 22 a and 22 b are made of a polymer, they haveflexibility. Thus, the antenna patterns 22 a and 22 b can be disposed ina wearable device. As a result, the degree of flexibility of design ofthe device can be improved.

In addition, with the switch devices 43 and 44, one of the antennapatterns 22 a and 22 b to be functioned can be selected. In addition, aplurality of antenna patterns 22 disposed on the antenna substrate 21can be freely controlled corresponding to desired frequencycharacteristics.

Next, a second embodiment of the present invention will be described.

According to the first embodiment, the antenna patterns 22 a and 22 bare disposed on the respective principal surfaces of the antennasubstrate 21. However, according to the second embodiment, two antennapatterns 22 a and 22 b are disposed on one principal surface of anantenna substrate 21. In the second embodiment, similar or correspondingelements to those in the first embodiment are denoted by similar orcorresponding reference numerals and their description will be omitted.

FIG. 9 is a sectional view showing an example of the structure of anantenna apparatus according to the second embodiment of the presentinvention. As shown in FIG. 9, the antenna apparatus 2 has a solidelectrolyte layer 24 and antenna patterns 22 a and 22 b disposed on oneprincipal surface S₁ of the solid electrolyte layer 24.

FIG. 10 is a block diagram showing an example of the structure of anantenna apparatus control circuit that controls the antenna apparatus 2according to the second embodiment of the present invention. The antennapattern 22 a disposed on the principal surface S₁ is connected to aterminal 43 a of a switch device 43 through a bias circuit 45 andconnected to a terminal 42 b of a switch device 42. The antenna pattern22 b disposed on the principal surface S₁ is connected to a terminal 44a of a switch device 44 through a bias circuit 46 and connected to aterminal 42 c of the switch device 42.

Next, the operation of a wireless apparatus 1 according to the secondembodiment of the present invention will be described.

FIG. 11 is a sectional view describing an example of the operation ofthe wireless apparatus 1 according to the second embodiment of thepresent invention. Next, with reference to FIG. 10 and FIG. 11, anexample of the operation of the wireless apparatus 1 according to thesecond embodiment will be described.

The terminals 43 a and 43 b of the switch device 43 shown in FIG. 10 areconnected. The terminals 44 a and 44 c of the switch device 44 areconnected. A DC voltage VDC is applied to the antenna apparatus 2 sothat the potential of the antenna pattern 22 a becomes high and thepotential of the antenna pattern 22 b becomes low. In other words, a DCcurrent i_(DC) flows as shown in FIG. 11.

When the voltage is applied, as shown in FIG. 11, ions of the antennapattern 22 b migrate to the solid electrolyte layer 24. Ions of thesolid electrolyte layer 24 migrate to the antenna pattern 22 a. Thus,the antenna pattern 22 b becomes an insulator, whereas the antennapattern 22 a becomes a conductor. In other words, only the antennapattern 22 a, which has been doped with ions, functions as an antenna.Thereafter, the terminals 42 a and 42 b of the switch device 42 areconnected. Thus, a radio frequency signal is supplied from the radiofrequency circuit block 41 to the antenna pattern 22 a. Since the restof the operation of the wireless apparatus 1 of the second embodiment isthe same as that of the first embodiment, the description will beomitted.

According to the second embodiment of the present invention, the sameeffects as the first embodiment can be obtained.

Next, a third embodiment of the present invention will be described.

In the second embodiment, the antenna substrate 21 is composed of onlythe solid electrolyte layer 24. According to the third embodiment, anantenna substrate 21 is composed of a solid electrolyte layer 24 and abase plate disposed on one principal surface of the solid electrolyte21. In the third embodiment, similar or corresponding elements to thosein the first embodiment are denoted by similar or correspondingreference numerals and their description will be omitted.

FIG. 12 shows an example of the structure of an antenna apparatus 2according to the third embodiment of the present invention. FIG. 13 is ablock diagram showing an example of the structure of an antennaapparatus control circuit that controls the antenna apparatus 2according to the third embodiment of the present invention. As shown inFIG. 12, the antenna apparatus 2 according to the third embodiment ismainly composed of a solid electrolyte layer 24; antenna patterns 22 aand 22 b disposed on one principal surface S₁ of the solid electrolytelayer 24; and a base plate 26 disposed on the other principal surface ofthe solid electrolyte layer 24. The antenna patterns 22 a and 22 b arefor example linear patterns or planar patterns. The linear patterns arefor example monopole type. The planar patterns are for examplemicrostrip type antennas or PIFAs (Planer Inverted F Antennas). As shownin FIG. 13, the structure of the antenna apparatus control circuit isthe same as that of the second embodiment. Since the rest of thestructure of the antenna apparatus 2 of the third embodiment is the sameas that of the second embodiment, the description thereof will beomitted.

According to the third embodiment of the present invention, the sameeffects as the first embodiment can be obtained.

Next, a fourth embodiment of the present invention will be described. Inthe first, second, and third embodiments, examples of which the twoantenna patterns 22 a and 22 b are disposed on the antenna substrate 21were described. In the fourth embodiment, however, an example of which aplurality of (three or more) antenna patterns are disposed on an antennasubstrate 21 will be described. In the following description, it isassumed that two antenna patterns are disposed on each of principalsurfaces S₁ and S₂ of the antenna substrate 21. In the fourthembodiment, similar or corresponding elements to those in the firstembodiment are denoted by similar or corresponding reference numeralsand their description will be omitted.

FIG. 14 shows an example of the structure of an antenna apparatus 2according to the fourth embodiment of the present invention. Antennapatterns 22 a ₁ and 22 a ₂ are disposed on one principal surface S₁ ofan antenna substrate 21. Antenna patterns 22 b ₁ and 22 b ₂ are disposedon another principal surface S₂ of the antenna substrate 21.

FIG. 15 is a block diagram showing an example of the structure of anantenna apparatus control circuit that controls the antenna apparatus 1according to the fourth embodiment of the present invention. In FIG. 15,for convenience, the antenna substrate 21 is omitted.

The antenna patterns 22 a ₁ and 22 a ₂ are disposed on the principalsurface S₁ of the antenna substrate 21. The antenna patterns 22 b ₁ and22 b ₂ are disposed on the principal surface S₂ of the antenna substrate21. The antenna patterns 22 a ₁ and 22 a ₂ disposed on the principalsurface S₁ are connected to terminals 61 a ₁ and 61 a ₂, respectively.Terminals 61 b ₁ and 61 b ₂ are grounded. Terminals 61 c ₁ and 61 c ₂are connected to a radio frequency circuit block 41.

The antenna patterns 22 b ₁ and 22 b ₂ disposed on the principal surfaceS₂ are connected to terminals 62 a ₁ and 62 a ₂, respectively. Terminals62 b ₁ and 62 b ₂ are grounded. Terminals 62 c ₁ and 62 c ₂ areconnected to the radio frequency circuit block 41. The terminals 61 c ₁,61 c ₂, 62 c ₁, and 62 c ₂ are connected to a voltage source (not shown)through a bias circuit 45.

FIG. 16 shows an example of the structure of a signal process circuitdisposed in the wireless apparatus 1 according to the fourth embodimentof the present invention. A switch device 55 selects one of the antennapatterns 22 a ₁, 22 a ₂, 22 b ₁, and 22 b ₂ to be connected to a switchdevice 54. The switch device 54 selects one of RF circuits 53 ₁, 53 ₂,53 ₃, and 53 ₄ to be connected to the switch device 55.

The RF circuits 53 ₁, 53 ₂, 53 ₃, and 53 ₄ are circuits that transmitand receive a radio frequency signal. BB circuits 52 ₁, 52 ₂, 52 ₃, and52 ₄ are control circuits that perform processes such as modulation anddemodulation of a signal. The RF circuit 53 ₁ and the BB circuit 52 ₁are circuits corresponding to the antenna 22 a ₁. The RF circuit 53 ₂and the BB circuit 52 ₂ are circuits corresponding to the antenna 22 b₁. The RF circuit 53 ₃ and the BB circuit 52 ₃ are circuitscorresponding to the antenna 22 a ₂. The RF circuit 53 ₄ and the BBcircuit 52 ₄ are circuits corresponding to the antenna 22 b ₂. Theantenna pattern 22 a ₁, the RF circuit 53 ₁, and the BB circuit 52 ₁ arean antenna and circuits corresponding to for example 5 GHz bands (IEEE802.11a). The antenna pattern 22 b ₁, the RF circuit 53 ₂, and the BBcircuit 52 ₂ are an antenna and circuits corresponding to for example2.4 GHz bands (IEEE 802.11b/g). The antenna pattern 22 a ₂, the RFcircuit 53 ₃, and the BB circuit 52 ₃ are an antenna and circuitscorresponding to for example UHF bands (DTV). The antenna pattern 22 b₂, the RF circuit 53 ₄, and the BB circuit 52 ₄ are an antenna andcircuits corresponding to for example MMW (Millimeter wave) bands.

Next, the operation of the wireless apparatus 1 according to the fourthembodiment of the present invention will be described. In thisoperation, it is assumed that only the antenna pattern 22 a ₁ of theantenna patterns 22 a ₁, 22 a ₂, 22 b ₁, and 22 b ₂ is functioned as anantenna.

First, the terminals 61 a ₁ and 61 c ₁ of the switch device 61 ₁ areconnected. The terminals 61 a ₂ and 61 b ₂ of the switch device 61 ₂ areconnected. The terminals 62 a ₁ and 62 b ₁ of the switch device 62 ₁ areconnected. The terminals 62 a ₂ and 62 b ₂ of the switch device 62 ₂ areconnected. Thus, a DC voltage V_(DC) is applied between the terminal 61c ₁ and the terminals 61 b ₂, 62 b ₁ and 62 b ₂ so that the potential ofthe antenna pattern 22 a ₁ becomes high and the potentials of theantenna patterns 22 a ₂, 22 b ₁, and 22 b ₂ become low.

When the voltage is applied, ions of the antenna pattern 22 a ₂, 22 b ₁,and 22 b ₂ migrate to the solid electrolyte layers 24 a and 24 b. Ionsof the solid electrolyte layer 24 a migrate to the antenna pattern 22 a₁. Thus, the antenna patterns 22 a ₂, 22 b ₁, and 22 b ₂ becomeinsulators, whereas the antenna pattern 22 a ₁ becomes a conductor. Inother words, only the antenna pattern 22 a ₁, which has been doped withions, functions as an antenna. A radio frequency wave is supplied fromthe radio frequency circuit block 41 to the antenna pattern 22 a ₁,which becomes a conductor. Since the rest of the operation of theantenna apparatus 2 of the fourth embodiment is the same as that of thefirst embodiment, the description thereof will be omitted.

According to the fourth embodiment, the same effects as the firstembodiment can be obtained.

Although the first, second, third, and fourth embodiments of the presentinvention were specifically described, it should be appreciated that thepresent invention is not limited to the first, second, third, and fourthembodiments. Instead, various modifications based on the technical ideaof the present invention can be made.

For example, according to the first, second, third, and fourthembodiments, values and structures described therein are only examples.If necessary, different values and structures may be used.

According to the first, second, third, and fourth embodiments, the solidelectrolyte has for example a planar shape. Instead, the solidelectrolyte may have for example a spherical shape or a polyhedral shapesuch as an ellipsoid shape, a cubic shape, or a cuboid shape.

According to the first, second, third, and fourth embodiments, only oneof a plurality of antenna patterns is doped with ions to function it asan antenna. Instead, at least two of a plurality of antenna patterns maybe doped with ions to function them as antennas. In this case, aplurality of antenna patterns need to be paired and spaced so that theydo not interfere with each other.

In the first, second, third, and fourth embodiments, the presentinvention is applied to the wireless apparatus 1, which can be attachedto and detached from the electronic apparatus 11 such as a personalcomputer. Of course, the present invention can be applied to anelectronic apparatus that has a wireless communication function as abuilt-in function. For example, the present invention can be applied toa portable information device that has a wireless function. In thiscase, since the antenna apparatus 2 can be disposed at any position, theelectronic apparatus such as a portable information device can be moreminiaturized.

In addition, the antenna apparatus 2 according to the first, second,third, and fourth embodiments may be adhered on the front surface of theelectronic apparatus such as a portable information terminal. In thiscase, the space for the antenna apparatus 2 can be omitted. Thus, theelectronic apparatus such as a portable information terminal can be moreminiaturized.

According to the first, second, third, and fourth embodiments, thepresent invention is applied to the wireless apparatus 1. Instead, thepresent invention may be applied to a wearable device.

According to the first, second, third, and fourth embodiments, aprotective layer that covers the antenna pattern 22 of the antennaapparatus 2 may be additionally disposed. The material of the protectivelayer needs to be a material that does not deteriorate thecharacteristics of radio waves of the antenna pattern 22. With thisstructure, the durability of the antenna apparatus 2 can be improved.

According to the first, second, third, and fourth embodiments, aplurality of antenna patterns corresponding to different frequency bandsare closely disposed. Instead, a plurality of antenna patternscorresponding to the same frequency band, but different centerfrequencies may be closely disposed to widen the frequencies with whichthe antenna apparatus 2 can deal.

1. An antenna apparatus, comprising: a substrate; and a plurality ofantenna patterns disposed on the substrate, wherein the antenna patternsbeing made of an electroconductive plastic, and wherein the substrate ismade of a solid electrolyte.
 2. The antenna apparatus as set forth inclaim 1, wherein the substrate has a separator, wherein solidelectrolyte layers made of the solid electrolyte are disposed on bothsurfaces of the separator.
 3. The antenna apparatus as set forth inclaim 1, wherein the plurality of antenna patterns correspond todifferent frequency bands.
 4. The antenna apparatus as set forth inclaim 1, wherein the plurality of antenna patterns are linear patterns.5. The antenna apparatus as set forth in claim 1, wherein the substrateis a planar substrate.
 6. The antenna apparatus as set forth in claim 5,wherein the plurality of antenna patterns are disposed on both principalsurfaces of the substrate.
 7. The antenna apparatus as set forth inclaim 5, wherein the plurality of antenna patterns are disposed on oneprincipal surface of the substrate.
 8. The antenna apparatus as setforth in claim 7, further comprising: a base plate made of a metal anddisposed on the other principal surface of the substrate.
 9. The antennaapparatus as set forth in claim 8, wherein the plurality of antennapatterns are planner patterns.
 10. A wireless apparatus that isconnected to a device and that allows it to additionally have a wirelessfunction, the wireless apparatus comprising: a substrate; a plurality ofantenna patterns disposed on the substrate; and a switch that selectsthe plurality of antenna patterns so that one of the plurality ofantenna patterns has one potential and the other of the plurality ofantenna patterns has another potential when a DC voltage is appliedbetween the plurality of antenna patterns; wherein the antenna patternsare made of an electroconductive plastic, and wherein the substrate ismade of a solid electrolyte.
 11. The wireless apparatus as set forth inclaim 10, wherein the substrate has a separator, and wherein solidelectrolyte layers made of the solid electrolyte are disposed on bothsurfaces of the separator.
 12. The wireless apparatus as set forth inclaim 10, wherein the plurality of antenna patterns correspond todifferent frequency bands.
 13. The wireless apparatus as set forth inclaim 10, wherein the plurality of antenna patterns are linear patterns.14. The wireless apparatus as set forth in claim 10, wherein thesubstrate is a planar substrate.
 15. The wireless apparatus as set forthin claim 14, wherein the plurality of antenna patterns are disposed onboth principal surfaces of the substrate.
 16. The wireless apparatus asset forth in claim 14, wherein the plurality of antenna patterns aredisposed on one principal surface of the substrate.
 17. The wirelessapparatus as set forth in claim 16, further comprising: a base platemade of a metal and disposed on the other principal surface of thesubstrate.
 18. The wireless apparatus as set forth in claim 17, whereinthe plurality of antenna patterns are planner patterns.
 19. Anelectronic apparatus having a wireless communication function thattransmits and receives information, the electronic apparatus comprising:a substrate; a plurality of antenna patterns disposed on the substrate;a voltage source that applies a DC voltage between the plurality ofantenna patterns; and a switch that selects the plurality of antennapatterns so that one of the plurality of antenna patterns has onepotential and the other of the plurality of antenna patterns has anotherpotential when the DC voltage is applied between the plurality ofantenna patterns, wherein the antenna patterns are made of anelectroconductive plastic, and wherein the substrate is made of a solidelectrolyte.
 20. The electronic apparatus as set forth in claim 19,wherein the substrate has a separator, wherein solid electrolyte layersmade of the solid electrolyte are disposed on both surfaces of theseparator.
 21. The electronic apparatus as set forth in claim 19,wherein the plurality of antenna patterns correspond to differentfrequency bands.
 22. The electronic apparatus as set forth in claim 19,wherein the plurality of antenna patterns are linear patterns.
 23. Theelectronic apparatus as set forth in claim 19, wherein the substrate isa planar substrate.
 24. The electronic apparatus as set forth in claim23, wherein the plurality of antenna patterns are disposed on bothprincipal surfaces of the substrate.
 25. The electronic apparatus as setforth in claim 23, wherein the plurality of antenna patterns aredisposed on one principal surface of the substrate.
 26. The electronicapparatus as set forth in claim 25, further comprising: a base platemade of a metal and disposed on the other principal surface of thesubstrate.
 27. The electronic apparatus as set forth in claim 26,wherein the plurality of antenna patterns are planner patterns.